1. Technical Field
The present invention relates to a liquid ejection control device that controls a liquid ejection device which uses a piezoelectric element and ejects a liquid having a pulsed shape.
2. Related Art
A technology, in which a liquid is ejected using a pulsed shape ejection pulse in order to cut a cutting target object, is known. Ejection of a liquid to have a pulsed shape means a jet flow of liquid is ejected from a nozzle in a pulsating manner, and thus, in this specification, the ejection is properly referred to as a “pulsed liquid jet.”
The pulsed liquid jet is variously used, and, for example, JP-A-2005-152127 proposes a technology which is used for performing surgery in the medical field. In this case, the cutting target object is a living tissue and the liquid is saline.
A mechanism which uses a piezoelectric element is one of the known mechanisms which is used to generate a pulsed liquid jet. In the mechanism, drive voltage having a pulsed wave shape is applied to a piezoelectric element and thereby, the piezoelectric element generates momentary pressure such that the liquid is ejected in a pulsed shape. Accordingly, in a case where strength of a pulsed liquid jet is changed, the drive voltage which is applied to the piezoelectric element is controlled. Therefore, it is conceivable to use a type of mechanism in which a characteristic value of the drive voltage which is applied to the piezoelectric element, such as a magnitude of a drive voltage waveform (voltage magnitude, also referred to as a size of drive voltage) is controlled by an operation unit such as an operation dial, an operation button, or the like, and thereby the strength of the pulsed liquid jet is changeable.
However, even when the characteristic value of the drive voltage which is controlled by the operation unit is changed, it is often not possible to change a cutting mode such as a cutting depth or a cutting volume of the cutting target object as intended by a user. A detailed description thereof will be provided below, and, for example, in many instances even when a user changes the voltage magnitude to be twice or four times, or half or one fourth of the magnitude, the cutting depth or the cutting volume is not necessarily changed at equivalent amounts. In a case where the pulsed liquid jet is used for surgery, a problem arises in that a surgeon's operation sense does not work as intended.
Meanwhile, if an ejection cycle of the pulsed liquid jet is changeable, it is possible to increase or decrease a cutting depth or a cutting volume per unit time and it is possible to adjust a speed of cutting a cutting target object. However, since the shape of the drive voltage waveform is changed when the ejection cycle is changed, the strength of a liquid jet for one pulse or the like can change. Accordingly, the cutting depth or the cutting volume obtained by a pulsed liquid jet for one pulse changes before and after the ejection cycle is changed, which can result in a case where a cutting speed proportional to an ejection frequency intended by a user is not obtained even when the ejection cycle is short, that is, when the ejection frequency is high.